Abstract:

To study the propagation sequence characteristic of hypervelocity impact induced acoustic emission (AE) waveform in Whipple shielding structure, impact tests against dual-wall structure are performed by using a two-stage light gas gun. A baffle panel is placed between the front/back panel of the dual-wall structure to prevent the debris cloud from impacting the back panel, AE signal induced by projectile impacting front panel is recorded by sensors in both front and back panel, the modal characteristics of the recorded signals are analyzed, the results suggest that AE signals in front panel are composed of A0, S0 and S2 modal waves, they are converted into A0 wave after propagated into the back panel. Based on the result, a prediction formula for arrival time interval between signals from the front and back panel is established. Then the baffle panel is removed, the coupling waveform of the AE signal induced by projectile impacting front panel and the AE signal induced by debris cloud impacting back panel are recorded by sensors in back panel, and the sequence characteristics of the two different signals are analyzed and compared with the formula predictions. The results prove the validity of the prediction formula.

Key words: Whipple shielding structure, Acoustic emission signal, Orbital debris, Debris cloud, Hypervelocity impact